Best of Both Worlds
by YappiChick
Summary: "What's a Halo?" / "I have no idea, Number One, but I suspect we will find out soon enough."
1. Chapter 1

**A long awaited response to the crossover conversation meme. Thanks to David for being so patient, encouraging and awesome while I tweeted my flailings, frustrations and snippets. This fic takes place after "All Good Things..." and before "Generations" in the ST:TNG universe and after Halo 4. This story is 100% complete (minus any last minute edits), so sit back and enjoy the crossover magic! :D**

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"This cannot be allowed to happen."

_"Certainly not. She has gone too far this time."_

"How has she managed to achieve so much without our permission?"

_"There are some who believe she has received the protection of the Precursors."_

"Rubbish! No Life Worker can be superior to the Continuum."

_"Her ability to proceed with her plan despite our disapproval belays that."_

"Do you dare question our power? We must intervene."

_"What about our commitment to the Mantle? We have sworn to never interfere with events of their time."_

"We will continue to uphold it. If, however, the humans were convinced to disregard her messengers on their own accord, it would be of no consequence to us. All it will take is one meddlesome member of the Continuum to ask the correct questions."

_"You do not mean-"_

"I do. He is the only one with experience with these...humans."

_"Can we trust him?"_

"He is a Q. We have no other option but to trust him."


	2. Chapter 2

**Sector 1195**  
**U.S.S. _Enterprise_, NCC-1701-D**  
**0525 hours, Stardate 48156.8**

Things had been too quiet aboard the _Enterprise_ recently. Since Captain Picard's latest encounter with Q, there had been nothing remarkable happening, outside of the captain joining the senior staff for their weekly poker game.

Worf started each shift double-checking the security logs from the previous night, careful to make sure that no one on his staff had missed anything important. He had yet to find anything, much to his annoyance.

The majority of his shift passed slowly. Routine scans. Random communiques from his security teams, reporting nothing of interest.

It was going to be another boring shift, he decided.

Captain Picard and Commander Riker walked onto the bridge at near the middle of his shift. "Status, Mr. Worf."

"There is nothing _to_ report, sir."

A grin passed over the commander's face. "Is that disappointment I hear in your voice?"

"Of course not, sir."

Another two hours passed. Commander Riker talked about a fishing trip when he was younger. Captain Picard spoke about Doctor Crusher's latest theater production.

Worf couldn't find it in him to be disappointed that he only had thirty minutes left in his shift.

Before he could begin to think about what he could do to make up for the tedious shift, a chirp sounded from his station. For a moment, he thought he imagined it, but as he looked down at the display, he realized that there was something wrong.

"Sir, sensors are detecting a subspace anomaly," Worf announced from his station.

Picard stood up from his chair, casting a glance at Commander Riker. Worf knew there was nothing in Starfleet records that showed that this area of space of susceptible to anomalies. "On screen."

There was a longer than normal pause from the Klingon. "Based on the readings, the anomaly is forming _on_ the _Enterprise_. Deck 4, main shuttlebay."

Will shot up from his seat. "Shields up."

Worf pressed several buttons and frowned. "Controls are unresponsive."

Picard took a step towards the Ops station. "Can we set up a containment field to contain it?"

Data's fingers flew over the controls. "Attempting to establish a static containment..." His voice trailed off and his fingers faltered. "Sir, I am detecting a life sign within the field."

Picard and Will exchanged a glance. Picard gave a slight nod.

"Worf, get a security team down there," Will ordered.

The Klingon nodded. He pressed several buttons on his console, ordering a half dozen men to the shuttlebay.

"Sir, creating a static containment field could potentially injure or kill whoever is trapped in the anomaly." Data tapped a few buttons. "Based on the computer's sensors, the anomaly is weakening. I believe that it will collapse within two minutes."

That was all the information Worf needed. He crossed the bridge, phaser in hand. Whatever was waiting down there, he wanted to be ready for it.

The ride in the Turbolift seemed to take longer than usual, but finally the doors opened and Worf approached the cargo bay. The rest of the security team stood outside the door, waiting in case anyone attempted to leave the bay.

_"Mr. Worf, please advised that the anomaly has collapsed on itself. Commander Riker and I will down shortly to greet our guest. Picard out."_

Worf frowned. They had no way of knowing who was beyond the door and he had no intention of allowing his commanding officers walk into there without it being secured. He approached the control panel, overrode the security code.

Moments later, the doors slid apart.

Worf cautiously stepped inside, phaser in hand. He looked around the bay, not noticing anything out of place. He tensed, preparing himself for a surprise attack.

He listened for any out of place sounds, but all he heard was silence.

Who would want to try to sneak aboard the _Enterprise_? The Ferengi? The Cardassians? Or maybe the Romulans had some new technology? The grip on his phaser tightened.

"Show yourself," he demanded. His eyes scanned the large containers in the corner, but he saw no movement. He walked to another stack of shipment containers when he heard it.

A faint groan came from his left.

When Worf spun around, he saw the intruder, laying on the ground. The person, wearing some kind of green armor, didn't move as he approached.

"Who are you?" he demanded.

The person didn't reply.

"What are you doing aboard the _Enterprise_?"

The bay doors opened behind him. Captain Picard and Commander Riker walked to Worf's position. "He has not responded to any of my questions."

Suddenly, the armored hand started to move. Worf's grip on his phaser tightened.

But, the man didn't make any moves towards them. He slowly reached up and lifted up the gold visor. As it slid up, Worf saw a face of a human.

"I need to get to Halo." Then, his eyes fluttered shut, slipping into unconsciousness.

Riker's brow furrowed. "What's a Halo?"

"I have no idea, Number One, but I suspect we will find out soon enough."


	3. Chapter 3

**Just a reminder that this fic is complete. So, no worries - it won't end up in the WIP graveyard. :D As always, thanks for the follows/favs/reviews. :D :D**

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"I'm telling you, Jean-Luc, I have never seen anyone like him before." Beverly sat behind her desk, looking at the medical readout from the John Doe that had mysteriously appeared on the ship.

Jean-Luc moved to stand next to the chair across from her. "But, he _is_ human."

She nodded. "Oh, absolutely. But, he's like no human I've ever encountered." She handed him a PADD full of medical readouts. "Carbide Ceramic Ossification. Catalytic Thyroid Implant. Occipital Capillary Reversal. Muscular Enhancement Injections. Superconducting Fibrification of Neural Dendrites. "

"In layman terms, Doctor."

She raised an eyebrow. "He's superhuman."

Picard looked up from the PADD. "Any idea how he got this way?"

Beverly shrugged. "He wasn't born that way, if that's what you're asking. There is evidence of heavy scarring all across his body. That would indicate to me that he had some extensive medical procedures performed on him. Based on the tissue, I would estimate they are decades old."

"Someone did this to him."

"As horrible as it sounds, yes. I was able to run a non-invasive scan on him-"

"Non-invasive scan?"

She nodded. "Even if I could take off his armor, which I don't think I could without Data or Worf's assistance, I don't know if it would injure him.\. But, I found something else on the scan." She tapped on her screen and spun the monitor towards Jean-Luc. A readout of the John Doe's skull appeared. "He has some kind of neural interface implanted in the back of his neck-"

A stricken look passed over his face. "Do you think the Borg is involved?"

"No," she quickly assured him. "There is nothing that even resembles Borg technology, but there is this." She pressed another button and the image zoomed in. "Based on my tricorder readings, it's some kind of isolinear chip. From best I can tell, it works with the armor and the neural interface."

Jean-Luc sat there for a second, processing all that she said.

She nodded towards sickbay. "He woke up a couple of minutes ago. Deanna's talking to him right now."

"What's your first impression?"

She thought about it for a moment. "I couldn't tell you, Jean-Luc. That helmet is hiding a lot."

"Well then," he said, raising his eyebrows, "let's see what else we can find out about our guest."

She led the way to where his patient was. Her jacket flared open as she walked ahead, brushing against Jean-Luc. He walked beside her.

As they approached the bed where their John Doe lay, Beverly noticed that the helmet he had been wearing had been removed. His pale skin made Beverly wonder if he had ever been exposed to sunlight or if he had lived under the helmet all of his life.

Deanna looked at the two of them. "This is John. He's a Master Chief in the UNSC," she said evenly.

Beverly and Jean-Luc exchanged a glance. There was no such thing as the UNSC as far as the doctor knew. Based on the look on Jean-Luc's face, he didn't know what Deanna was referring to either.

Beverly kept her frown hidden from her patient. None of the scans showed signs of blunt force trauma. Perhaps he had some sort of mental illness that she hadn't been able to detect.

"The UNSC?" Jean-Luc asked.

The Master Chief sat up slowly, throwing his legs over the edge of the medical bed. Beverly's breath caught in the back of her throat. This man, in some kind of robotic armor from the neck down, reminded her of Jean-Luc when he had been brought into sickbay after he had been transformed into Locutus.

Deanna looked at her, concerned. Beverly gave a curt nod. Now was not the time to reflect on those times.

"The United Nations Space Command." His voice is rough. Beverly noticed his quick glance to his collar. "Sir," he added quickly.

Picard shifted his weight from one leg to another. "I'm afraid that I'm not familiar with that organization."

Beverly picked up a nearby tricorder and started running another scan on the man, allowing Jean-Luc to lead the conversation.

"It doesn't exist here."

He didn't offer any further explanation. Beverly gave a half-shrug when Jean-Luc looked at her questioningly. Nothing on the readings she was getting showed any sign of mental illness.

"When you first arrived here, you mentioned something about a Halo," Jean-Luc prompted.

John lifted his hand. In it, there was an object that looked similar to an isolinear chip. That must have been what was in his neural lace, Beverly realized. "We need to repair Cortana. She's the only way."

"The only way to what?"

"To complete our mission."


	4. Chapter 4

**Onwards with the story! As always, thanks for the follows/favs/reviews. :D :D**

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The senior staff sat in the conference room, after the captain had called a impromptu meeting. Picard sat at the head at the table while Will sat in his right. On the left, separated by a couple of chairs from Deanna, the Master Chief sat.

"As you all know, at 0525 hours today, the _Enterprise_ detected a subspace anomaly which transported the Master Chief and his AI companion on board," the captain started. "According to the information he has provided, he and his AI companion have been sent on a mission from an entity called the Librarian."

Will cast a quick glance at the newcomer. He hated the fact that he couldn't see the Master Chief's face. Over the years, playing poker had made Will into someone who could read anyone based on their body language. However, when he looked at the Master Chief, all he saw was a distorted reflection of the room in his visor.

He shifted his gaze to Deanna. Years of knowing her allowed him to see through the face of neutrality. She was curious about the newcomer, but Will didn't sense any concern from her.

It didn't make him feel much better though.

"The Librarian is a member of a species known as the Forerunners. It is, according to the Master Chief, an ancient race that was a sort of precursor to humanity as we know it." Picard leaned back in his chair. "They were nearly extinct. Only a handful of them managed to put themselves in a sort of status field - a cryptum- which kept them alive for over one hundred thousand years."

Across the table, Geordi let out a low whistle.

"What happened to the others?" Will asked.

"After being under attack by a hostile creature known as the Flood, they activated what they call the Halo array. The result of this was that nearly every lifeform in its attack path was killed. The universe was subsequently repopulated due to a so-called Conservation Measure," Picard continued.

"I am afraid that there are no records to indicate that anything like that ever happened, sir." Data cast a glance at the Master Chief.

"That's because it didn't occur here. The Master Chief is not from this timeline," the captain replied evenly.

Will had to hand it to Picard. He didn't know if he could repeat all of that without letting his skepticism seep into his voice, talented poker player or not.

"He is from another timeline?" Worf asked. The Klingon didn't even attempt to hide his suspicion.

"Yes." It was the first time the Master Chief spoke. "The year 2552."

Will watched as a confused look pass over Data's face, but the android voiced no question.

"I've contacted Starfleet Command and they have authorized us to investigate the coordinates that the Master Chief has provided. I have already had Ensign Rogers set a course for the Halo ring," Picard said. "Meanwhile, I want Mr. Data and Mr. La Forge to work on repairing the chip that houses the Cortana program."

The Master Chief stiffened.

"If that's alright with you, Master Chief."

"Of course, sir." It was difficult to tell under the layers of armor, but it seemed to Will that he was hesitating to hand Data the chip in his hand.

"Commander La Forge and I will do everything we can to repair your chip. If we cannot, we will not do anything that will damage it further." Data reached out to take the crystal from him.

The Master Chief released his hold on the chip. "Thank you, sir."

Data studied him for a second. "Perhaps it would be to our advantage if you were to go with us to Engineering. Since your suit is calibrated to interface with the data crystal, your presence would prove to be most helpful."

Geordi nodded. "I agree, Captain. I _could_ duplicate the energy signatures from the Master Chief's armor, but it'd save us a lot of time if he was working with us."

Picard nodded. "Very well. You three go to Engineering. If there is any progress, I want to be contacted immediately."

The three men nodded. "Dismissed."

Will waited until the doors closed behind the trio before looking at Deanna. "What's your take on him?"

"He believes everything that he is saying. There is nothing that I can sense from him to indicate that he is being anything less than truthful," she replied.

Beverly added, "I ran additional scans on him and there are no signs of mental illness. He is beyond the picture of good health. For being 46 years old, he has the body of a man in his late twenties."

"Either he really is from the future in an alternate timeline or he has fooled everyone on this ship, including himself," Deanna replied.

"What about this Cortana?" Will asked.

"Whoever she is, he is very concerned with her. This isn't some random computer program." Deanna answered.

"Do you think Geordi and Data will be able to repair her?"

Picard raised his eyebrows. "Something tells me that he's not going to take no for an answer."


	5. Chapter 5

**Onwards with the story! As always, thanks for the follows/favs/reviews. :D :D**

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It had taken the better part of three hours and some creative tinkering, but finally Geordi and Data had rigged up a contraption that would allow them to access the Cortana program housed in the chip the Chief had brought onto the _Enterprise_. Geordi ran a final diagnostic, then gave a nod when the results appeared on the screen. "We're as ready as we're going to get."

Geordi looked at Data and then, the Master Chief. The android seemed unusually short standing next to the seven-foot tall man in armor.

Despite the fact that he had been with them since they had left the conference room, the Chief offered little of his personality. So far, the Master Chief had limited himself to short answers, always ending with "sir".

Geordi set the modified isolinear chip reader on top of the display unit. A thick cord ran from the back of it and plugged in directly to the main computer port. Data stepped forward and slid the chip in the reader.

Almost immediately, the lights in Engineering dimmed.

"Warning," said the ship's main computer calmly, "data saturation levels nearly maximum capacity."

Geordi's fingers flew over the control panel, shutting off the reader. The binary code was still streaming across the screen as the ship attempted to process all of its data.

Just how much information was stored in Cortana?

Geordi exchanged a glance with Data who seemed as off-guard as he was. If they couldn't find a way to filter the information entering into the _Enterprise'_s computers, they wouldn't have a chance to try to repair Cortana.

Seconds later, his communicator chirped. "Geordi, what's going on down there?" It was Commander Riker.

"I underestimated the amount of data that this data crystal contained. It temporarily caused the computers to be bogged down, but it's under control now," Geordi admitted. "We've shut off the interface until we can create a buffer."

"Understood. Riker out."

Geordi exchanged a glance with Data. "Have you ever seen so much data on one chip before?"

Data shook his head. "No. It is quite impressive." He turned to the Master Chief. "Tell me, are there many programs like Cortana?"

"Not anymore."

An awkward silence settled between them.

It was Geordi that broke the tension. "It's going to take me some time to figure out just how to start creating a buffer."

"If I may suggest..." Data looked at the Master Chief. "The back of your helmet contains AI housing, does it not?"

"Yes."

"Then, hypothetically, Geordi and I should be able to use it to filter the amount of data that enters into the _Enterprise_'s systems," Data said.

Geordi nodded slowly as if considered his friend's solution. "That could work."

The Master Chief looked down at them. "What do I need to do?"

"Simply remove your helmet," Data replied. "We will not know what adapters we will need until we are able to see it."

For a moment, Geordi wondered if the Master Chief was going to do as the android suggested. But, slowly, the Chief lifted his hands and released the locks on the helmet. Seconds later, he lifted the helmet up and carefully handed it to Data.

It was clear that he was uncomfortable being exposed. Geordi wondered how long it had been since he had taken off his helmet.

Geordi watched as Data inspected the back of the helmet. "I believe I can find an adapter to interface with this." He placed the helmet beside the chip reader. "I will be back shortly."

Before Geordi could offer to find the part, Data had walked away leaving him alone with the Chief. Normally, the Chief Engineer could become friends with anyone, but he suspected that this man was not in the mood to make acquaintances with anyone.

Still, it could be a while until Data returned. "So, Master Chief-"

"Chief," he corrected.

Well, that was a start, Geordi thought.

"Chief," he started again before he realized he didn't know what to say. He studied him for a second. His VISOR was picking all sorts of energy signatures from his suit. There was even a faint reading coming from the back of his neck.

His eyebrows furrowed. "You have a neural implant?"

"Yes." There was a pause. "How did you see it?"

"You're not the only one with a neural implant, Chief?" Geordi tapped his temple. "I've got two of them. It allows me to interface with my VISOR to see."

"You can detect energy signatures with it."

Geordi nodded. "I can't see like most humans, but it has come in handy from time to time." He nodded towards the Chief. "What is yours for?"

"It acts as an IFF." There was a long pause. "Cortana's program-"

"I believe I have found a suitable adapter." Data's voice cut off the Chief's words. He glanced between the two men. "Was I interrupting?"

"It was nothing," the Chief said.

Data took him at his word and handed Geordi a small adapter that was attached to a short wire. Geordi reached around and connected it to the chip reader as Data plugged it into the back of the Chief's helmet.

When he finished, he gave Geordi a quick nod.

Geordi took a deep breath. "Let's try this again."

This time when he activated the reader, he stayed near the controls, ready to shut it down if necessary.

"Fascinating," Data said from another console.

Confident that the Chief's helmet was providing enough a buffer from the _Enterprise_'s systems, Geordi walked to where Data was.

"I am noticing that there appears to be a large amount of redundant data within her matrix," Data said, glancing at the Chief.

His body tensed. "It's the rampancy."

Data's eyebrows went down. Geordi was as confused as he was. "I am afraid I am unfamiliar with that term."

The Chief shifted his gaze away. "She's dying."

An interesting word choice, Geordi thought. Then again, if Data's systems were to start slowly shutting down, he would use that same term.

Data pressed a few buttons. "I am sorry to hear that. Perhaps there is a way to get her program functioning properly again."

Geordi frowned. They didn't even know the first thing about how her program even worked. "Data, we don't even know if we can get her program working in the first place," he reminded him.

"I am confident that I will be able to do that," Data said assuredly. "However," he looked at the Chief again, "it will longer than we anticipated. Perhaps you will find your time better spent resting in the quarters Captain Picard has provided for you."

The Chief whipped around to face him. Geordi lifted his hands. "We will contact you as soon as we find anything." He looked at the data. "It's just going to take some time."

Several seconds passed before the Chief finally gave a curt nod. Then, he spun around and left the two of them alone.


	6. Chapter 6

**Whee! As always, thanks for the follows/favs/reviews. :D :D**

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**En Route to Sector 2569  
**U.S.S. _Enterprise_, NCC-1701-D  
0245 hours, Stardate 48156.8

The Master Chief was impossible to miss.

It had been over two weeks since the _Enterprise_ had acquired their unique passenger and this was the first time she had seen him.

The bulky armor he wore stood out starkly in comparison to the form-fitting Starfleet uniforms the officers wore.

Guinan watched as he entered and scanned the room before crossing it. His stride was confident, but there was a tension that she could easily detect.

It was clear that he didn't want to be in Ten-Forward which made her all the more interested in why he was there.

After several seconds of glancing at the area, she watched as he moved towards a table in the back corner of the room. He was mostly hidden from the others in the room, but his position allowed him to have a view of everyone around him.

He had barely sat down in the too-small chair before Guinan nodded at the bartender down the counter. "Cover me."

She slid from behind the counter and made her way to the Master Chief. As she approached his table, she offered him a friendly smile. "Welcome to Ten-Forward. Can I get you anything?"

He shook his head. "No." A half-second passed. "Thank you."

She had been right in her early assessment; he didn't want to be there. Now she had to figure out why he had come into her domain.

Good thing she had always liked a good mystery.

"I don't think I've seen you in here before." She nodded towards the chair opposite of him. "Can I join you?"

She knew he wanted to say no. Guinan saw the slight frown that passed over his face. In the end though, he nodded. "Go ahead."

Guinan sat down, studying the man in front of her. If it wasn't for the lack of pointed ears, she might have pegged him for a Vulcan. He was certainly stoic enough to pass as one. "So, what's your name?"

"Master Chief."

Her eyebrows rose at his answer. "I asked for your name. Not your rank."

When he didn't answer immediately, she smiled patiently. "I'll start. My name is Guinan."

For the first time since she had approached him, he looked her right in the eye. "John," he finally replied.

A smile spread across her face. "Now that wasn't so difficult, was it?"

He didn't reply.

"So," she said, refusing to let the opportunity of a conversation pass, "it's not often that we get a visitor from another timeline."

He glanced at her clothing. "You're not a Starfleet officer."

"No," she conceded. "But working in here has its perks. You hear things." She leaned back in her seat. "Rumor is that you were sent from the mid-26th century from an alternate timeline. Your mission must be pretty serious for someone to go through all that trouble to send you here."

"It is."

She nodded out the window to where the stars were streaking past the window. "People may have also mentioned that the _Enterprise_ is on its way to investigate some sort of alien artifact. I don't suppose you know anything about that."

John didn't answer right away. Guinan made herself comfortable. She could wait.

Finally, he said, "A Halo ring."

A sinking feeling settled in her stomach. "Forerunner," she muttered.

His eyes narrowed. "Did the rumor mill tell you that too?"

"No." Suddenly, the mystery of the Chief's arrival in Ten-Forward seemed trivial to finding out why he was sent in this timeline.

She leaned forward, across the table. "The El-Aurian, a race of listeners and extraordinarily long life, were said to have been the offspring of a faction of Forerunners and humans who fled from the Master Builder to form a colony together." She saw the confused look on John's face. "The El-Aurian are my people."

He shook his head slightly.

She folded her hands. "I take it that didn't happen in your timeline."

"No, but Cortana-" He stopped abruptly. He closed his eyes briefly, then looked at her. "How did you know what the Halo ring is?"

"My grandfather used to tell me a story that had been passed down to him about the Forerunners' curse. A ring world that could destroy the entire universe. He called it 'Halo'." She pinned John with a worried look. "It gets activated, doesn't it? That's why you're here."

She watched as he hesitated briefly. Finally, John nodded. "Yes. In six months from now, a survey team will find it. A year from then, Starfleet Command will issue the order to fire the ring. Their actions will not only kill the Borg they were trying to defeat, but all living life in the quadrant."

She studied him for a second. "What is your real mission, John?" she asked.

Before she could answer, a flash of red caught her eye. Captain Picard was coming up to the both of them, to talk to John presumably.

"I should be getting back to the counter," she said, standing up. "If you wouldn't mind, when all of this is over I'd love to have a long chat with you about my ancestors over a glass of Romulan Ale."


	7. Chapter 7

**Onward with the crossover magic! As always, I'd love to know what you think! :D :D  
**

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**En Route to Sector 2569  
**U.S.S. _Enterprise_, NCC-1701-D  
0245 hours, Stardate 48156.8

Guinan barely stepped away before the captain started to walk over to his table. If it hadn't been for Counselor Troi's insistence that he take some time away from Engineering and come down to Ten-Forward, he would have never dared to venture down to the room of camaraderie and mixed drinks.

He was too exposed here. He would much rather be alone.

He closed his eyes briefly and saw an image of a blue-hued woman looking at him accusingly.

Cortana.

Well, maybe not alone, he conceded.

He knew Commander La Forge and Commander Data were diligently trying to do what they could to save Cortana's life. A life that, in all likelihood, couldn't be restored.

_"John, I don't want you to see me like this." __He slowly approached her. He didn't know what he would find when he left the Inifnity with nothing more than a glimmer of a possibility that Cortana was on a Forerunner installation. Her avatar turned away from him, her face was hidden. "I'm not what I was." She let out a shaky sigh. "I'm only a fraction of the person you knew."_

_He looked at her, curled up in a fetal position, not unlike how he had found her on _High Charity_. But, he knew as he saw her struggle to stand, that it was different than the last he had saved her from the Gravemind. Still, he refused to give up on her. "You're Cortana. You know I would never leave you behind." _

_She looked at him, with his armor beaten by the sands and a ripped poncho over him. "Stubborn fool."_

_"You're going to be fine."_

_Her smile didn't quite meet her eyes. "I hope you're right, John."_

For a while, it had been. They had found the Librarian who had given up all of her knowledge concerning advanced constructs. Cortana had been more like herself since before John had awoken from the _Dawn_. But, the task they had been charged with was difficult, and came at a price. It hadn't taken long for Cortana's rampancy to return, more quickly than it had before.

_"I'm so sorry, John."_

"Is this seat taken?"

The soft-spoken question pulled John from thoughts about Cortana. He gave a quick shake of his head, wondering why the captain had decided to seek him out.

Picard slid into the chair, his face passive. "How are you enjoying your time aboard the _Enterprise_, Master Chief?" This was the first time in two weeks that the captain had asked him that question.

He looked away from his observation of the universe as it whizzed by at warp drive. It was different than traveling through slipspace.

But, John thought as he glanced at the man sitting across from him at the table, everything was different aboard the _Enterprise_.

"It's not the same from my timeline." He missed the familiarity of the UNSC. Here, things seemed almost utopian; John couldn't say he was particularly comfortable with it. "It's more quiet."

"You say that as if it's a bad thing." The captain offered a friendly smile.

John looked at him blankly.

The captain cleared his throat. "I see that you are taking advantage of some of our amenities. Guinan has added her own personal touch to Ten-Forward."

Guinan. The woman who claimed to have Forerunner heritage. Not for the first time, John wished Cortana was there to tell him whether her claim could be true or not.

"We met."

Picard shifted uncomfortably before speaking again. "I wanted to give you an update on the damaged computer program-"

"Her name is Cortana, sir."

"Of course. My apologies." He at least seemed to look contrite, John noticed. "Commander Data and La Forge are working as best they can, but, despite your assistance, I am concerned they won't be able to do anything for her."

John frowned slightly. "She needs to be here. The Librarian gave her the Key."

"Yes, the Librarian." Picard looked John square in the eye. It was then that the Spartan realized that the captain didn't necessarily believe him. A nervous feeling settled in his stomach; if he couldn't convince Captain Picard to allow his officers to continue trying to repair Cortana, his mission would be a failure. "We will proceed to the coordinates that you provided, but if by that time Cortana's program is not functioning properly, I will be forced to reassign my officers to more pressing matters."

John couldn't think of anything more pressing than getting Cortana back to operating properly. Years of discipline and respect of the chain of command kept John from voicing his opinion. Instead, he offered a half-hearted, "Understood, sir."

The Spartan expected for the conversation to be over so he was taken aback when the captain leaned forward, resting his arms on the table.

When Picard spoke again, his voice was much quieter than it had been before. "Commander Data believes it is possible to create another program based off the data that is stored on the chip."

"No." His tone left no room for argument.

The captain's eyebrows moved up in surprise. "I see." He paused. "If, as you say, your resources are on her chip, I thought I should present the possibility to you."

John shook his head. "She'll be fine."

"I hope for everyone's sake that you are correct, Master Chief." Cortana's words echoed through his mind. How many more times would he futilely try to convince everyone - and himself- that Cortana would be alright?

The captain stood up and left John alone.

Across the room, he saw Guinan watching him closely.


	8. Chapter 8

**Onward with the crossover magic! As always, I'd love to know what you think! :D :D  
**

* * *

**En Route to Sector 2569  
**U.S.S. _Enterprise_, NCC-1701-D  
0245 hours, Stardate 48156.9

"And then I decided to request for a transfer off the _Enterprise_."

Beverly's words cut through the fog of distraction in his mind.

Jean-Luc looked across the table, with a plate of croissants and two cups of coffee, stricken. "What did you say?"

An impish look passed over her face and he realized that she hadn't been serious. "You haven't heard anything I have said since I walked in this morning," she accused.

She was correct, of course.

Despite the necessity of pulling Data and Geordi from repairing Cortana after they reached the Halo ring, there was a lingering guilt that pressed upon him after his conversation with the Master Chief from the day prior.

Jean-Luc might have questions to the validity of the Chief's claims - whether or not there was really going to be something waiting for them at the coordinates was yet to be seen - but there was no doubting the pain that flashed across the young man's face when he had offered to replace Cortana.

"Jean-Luc, you're not listening again."

He looked at Beverly who had a concerned look on her face. He shook his head, clearing his thoughts. "I'm sorry. I'm afraid I am rather distracted this morning."

She raised her cup to her lips and took a sip. "Does this have anything to do with reaching the Halo ring?" she asked.

"Indirectly," he replied. Then, he told her about the exchange he had with the Master Chief in Ten-Forward.

When he had finished, she leaned back in her chair. "And this concerns you?"

"Yes." He raised his eyebrows. "I'm afraid what will happen if Data and Geordi can't repair her." He let out a sigh. "For the first time since he's been on board, he seemed completely human."

"He _is_ human," she countered. "Don't let the armor fool you, Jean-Luc."

"I know that, Beverly." He frowned.

Beverly shrugged. "Then, his reaction is to be expected. Based on the readings we got from the neural link, she was _in_ his mind." She gave him a pointed look. "You, of all people should know how that feels."

"Kesprytt." The word carried across the room.

Beverly nodded her head. "And we only had that connection for a day." She took a sip of her coffee. "I don't know how long he worked with Cortana, but it's clear based on the scans I took of the neural link that it was intended to be a long-term arrangement."

She broke off a piece of croissant. "Honestly, I'd be more concerned if he _didn't_ show some sort of emotion."

"True," he conceded. "Still, I have no choice but to let my order stand."

"I'm sure he understands that, Jean-Luc."

The rest of the breakfast passed. Jean-Luc did his best to concentrate on his conversation with Beverly, which had moved onto the topic of how long they planned to stay at the Halo ring, but his mind kept going back to the Master Chief.

It was somewhat of a relief when his communicator chirped. _"Data to Captain Picard."_

"Picard here."

_"Sir, I need you to come down to Holodeck 3."_

A spark of hope blossomed in him. "Did you manage to repair Cortana?"

_"Negative_." The spark sputtered out. "_However, Geordi and I are attempting to test a new theory. I am hopeful that we will be able to activate a portion of her program._"

Hope sprung back to life. He exchanged an optimistic look with Beverly. "I'm on my way. Picard out." He stood up from his chair. "I'm sorry to cut our breakfast short."

"It's alright, Jean-Luc. I'll just talk to myself like I have been doing all morning." Her eyes crinkled with mirth for a moment before turning serious. "I hope Data can figure something out."

"So do I."

/*-/*-/*-/*-/*-/*-

Like Sherlock Holmes, Data enjoyed a challenge.

Often, his struggles were of a personal nature. The quest to become more like the humans around him. The study of how and why people behaved in the ways they did and how he could adapt his program to be more like them.

He was the peak of artificial intelligence. There was nothing that compared to him.

Until the Chief brought Cortana on board.

For two weeks, Data had spent his spare time trying to repair the program that seemed impossibly complex. During a late night work session, the Chief had told him that her programming was created from a human's cloned brain.

More often than not, Data found himself working with Geordi or the Chief. He didn't mind the company. The Chief had insight into how Cortana's program worked and Data always enjoyed working alongside his best friend.

He and the Chief Engineer had been working that morning when Geordi had come up with their most recent attempt to reactivate the Cortana program.

"What if we upload a fragment of her program to the Holodeck?" Geordi had asked earlier in the day. "If we can piece together enough data to activate her holographic interface, she might be able to help up figure out how to repair the rest of her."

With that suggestion in mind, Data set off to do that very thing.

It had taken him just over two hours, but he felt confident that he had filtered enough of the redundant data to be able to establish some sort of connection with Cortana's interface.

He had contacted Captain Picard and the Master Chief and was waiting for them to arrive in the Holodeck.

Geordi raised his eyebrows. "I hope this works."

Data did too. He was aware of the captain's order, which meant they had seven hours, twenty-one minutes to get Cortana functioning properly.

The doors behind him slid apart. The Chief walked in, glancing at the mostly empty room. "Where's Cortana?"

"We're waiting for the captain," Geordi replied. "As soon as he gets here, we'll be ready to try our plan, Chief."

The Chief nodded, glancing at his helmet. "Will it work?"

Geordi looked at Data who nodded. "I would not call you and the captain down if I did not have full confidence in what we are about to attempt to do."

Less than a minute later, the doors once again opened. This time Captain Picard walked in and looked at Data expectantly. "Are you ready proceed?"

Geordi nodded. "As ready as we're going to be."

"Make it so."

A tension settled over the room as Data moved to stand in front of the control panel. It was a hologram, but Data had linked it to the _Enterprise_'s main computer, making it as functional as the terminal he had been using in Engineering.

Several seconds passed as Data continued to implement the protocol to Cortana's chip. Then, a glimmer of blue started in appear in front of the terminal.

Data didn't know what to expect when he saw Cortana, but seeing her as a half-naked blue woman wasn't it.

Immediately, Captain Picard looked away and Geordi blushed. Only the Master Chief seems unperturbed by her state of undress.

"John?" She walked up to him and pressed her hand to his cheek.

Geordi averted his gaze as well, but Data had no such compunction. He watched in fascination as a pained look past over the Chief's face.

"How did I get here?" she whispered, letting her hand drop.

"Later."

She gave a curt nod and looked around the room. Data watched as the vulnerability on her face melted into an impish expression. "I almost didn't recognize you without the helmet, you know."

"Cortana-"

Then, suddenly, she put her hand up to her head, as if in pain. "I can't access my files, John."

Data interjected himself in the conversation. "I am afraid that your program is too complex for our ship's computers to process. We have had to use the Master Chief's interface through his helmet to filter the data."

"I always knew I was too much woman for most people to handle." She turned to Data. "Let me guess, you activated just enough of me so I could help you piece me back together again."

Data eyebrows rose in surprise. "You are correct."

"How much..." She trailed off, casting a quick glance at John before looking back at Data. "How much data degradation has there been?"

"I estimate that there twelve percent of your matrix is corrupted due to the redundant data loops, but I hypothesize that I could implement a program that could eradicate them, therefore resolving the issue that the Chief refers to as rampancy."

"Don't." She stopped him, holding up a hand. "Let's on work on getting me back to working form before you offer me my lifelong dream."

"We'll be arriving at the Halo ring in less than eight hours," the Chief said. "You'll need to be ready."

She frowned briefly. "That should be enough time."

"It has to be."

"I know, Chief."


	9. Chapter 9

**Onward with the crossover magic! As always, I'd love to know what you think! :D :D  
**

* * *

Deanna knew the moment Cortana's program had been reactivated.

She had been sitting in her usual chair on the bridge when an overwhelming presence pervaded her mind. There were so many emotions and turmoil that flooded her. It took her a half-second to shield herself from the unexpected raw emotion.

Melancholy. Angry. Jealousy. Hate. But, stronger than all of those, a deep feeling of longing that nearly caused Deanna to gasp.

Her tension was not unnoticed. Will looked at her from the captain's chair. "Everything alright?" he asked, a slight worry entering into his voice.

She nodded her head and pasted a smile on her face. She blocked as much of the powerful emotion as she could. "I'm fine. It's just...Cortana's program was activated."

"And you could feel that?"

She nodded, allowing herself to slowly process Cortana's feelings. "Well, I was able to sense Data's emotions when Lore installed the emotion chip. I imagine it works the same way for Cortana." Deanna settled back in her seat. She wanted to raise a hand to her head, to try to bring clarity to what she was sensing from Cortana, but she knew it would only worsen Will's increasing worry.

Will studied her for a second. He knew she was hiding something from him. "What is it?"

She lowered her voice so only the two of them could hear each other. "I'm detecting a lot of...noise." She frowned as an explanation eluded her. Will might be her Imazdi, but there were things as an empath that she couldn't easily relate to him.

"Noise."

She nodded. "The best way to describe it is that it's like when I'm near someone who is suffering from psychological disorder."

Immediately, Will tensed. "Should I contact the captain?"

"No." She shook her head. "She's not dangerous. Just...confused." She shrugged. "For all we know this is just a side-effect of Data having to divide her program. It's probably nothing to worry about."

"I hope so." Will blew out a frustrated breath.

"I wouldn't worry about it, Will. According to what the Chief said, the two of them used the neural link for a long time and Beverly detected no neural damage on her scans," she continued.

Another minute passed and Deanna was able to relax slightly. She gave Will a reassuring smile.

He frowned slightly. "Do you still believe the Master Chief? That there is some kind of floating ring in the middle of the galaxy?"

"I do." Despite being there for over two weeks, there were many things about the Chief that were shrouded in mystery, even to her. But, she didn't doubt the validity of the Chief's claims about the Halo ring. The strength of the Chief's convictions extinguished any doubts she might have had.

"Besides, what purpose would he have to lie to us?" she wondered.

"To fix his broken AI?" he retorted, settling back in the chair.

Deanna didn't have a response to that.

Hours passed. Cortana's presence was no longer as oppressive as it had first been. Over time, her emotions leveled out and Deanna was able to relax.

"Commander, we're picking up something on long-range sensors," Ensign Jameson reported from the comm station.

Deanna watched as Will's eyebrows rose. Perhaps she wouldn't have to defend the Chief and his claim any more.

"On screen."

A half-second later, a small object appeared. Wll stood up from the chair. "Magnify."

The image was a little grainy, but there was no doubt what Deanna and the rest of the bridge crew were looking at: a giant ring floating in the middle of space.

"It's Halo," Deanna said.

"Contact the captain, tell him he's needed on the bridge," he said to the ensign. He walked back to Deanna and sat down in the chair. "I guess this means I owe the Chief an apology."

/*-/*-/*-/*-/*-/*-/*-

Q always had to be the one who had to fix everything.

He had tried to warn his brethren that humans were far too curious for their own good. He had known that Data would get the ancilla working again, despite the staggering odds against success. If his time as a human taught him anything, it was that the android didn't give up on anyone.

Despite the optimistic android, Q had another reason for knowing that the _Enterprise_ would continue their search for the Halo ring. _Her. _Q knew that if _she_ had sent these two renegades, the universe was not going to deny her after all she had suffered.

It wasn't fair that he had to be thrown in the middle of this, really.

But, the Continuum had been resolute. He knew the most about humanity. He had interacted ("meddled," Q2 had said smugly.) with the crew of the _Enterprise_ so often, it was up to him to convince Picard to listen to him rather than the two travelers since by the Life Worker.

He might have been omniscient, but even he recognized that some things were just impossible to accomplish.

Still, the Continuum had spoken and he was forced to comply.

With a quick thought, he moved to the _Enterprise_, morphing into the human body the crew knew and loved. (Well, he wasn't so sure about the loved part.)

On the bridge, he recognized the regular bridge crew and looked at the two characters who looked oddly out of place in the carpeted bridge. The man was wearing green armor that looked like it had seen better days and was holding a crystal with a small holographic woman projecting from it.

He inwardly sighed. She had over a hundred thousand years to come up with some sort of master plan and this was it? He almost felt sorry for her.

He appeared next to the science station where Data sat, facing Picard and the rest of the bridge crew. "I had no idea it was your habit to take interdimensional hitchhikers, Jean-Luc. Starfleet continues to surprise me."

"Q!" Picard said, frowning. "What are you doing here?"

Q had no intention of answering his obscenely obvious question. He walked up to the tall man and looked him up and down. "Do you even try to use that tiny brain of yours or do you just expect for me to hand you all of the answers, no matter how glaringly obvious?"

He watched as Worf stiffened. Honestly, it was so easy to get under the Klingon's skin.

"And," he said, bending down low enough to be eye-to-eye with the blue hologram. "A tiny woman made of light. Starfleet's standards are as rigorous as ever, I see."

This time is was the Spartan that stiffened.

Picard moved towards him. "Again, Q, what are you doing here?"

"Can't a friend stop by and visit?"

"Yes, but you are no friend."

"Jean-Luc, you wound me." He put a hand over his chest for good measure. "And after I helped you save humanity."

"You still haven't answered my question."

"My, we're feeling awfully dogmatic today. Has some of Worf's tenacity rubbed off on you?"

Picard said nothing. He only crossed his arms while he waited for the answer he was demanding.

Q sighed. Why did Jean-Luc always have to act like a spoiled child who sulked when he didn't get his way? "Fine. I've come to see what your mission is."

He watched as Picard and Riker exchange a glance. It was the first officer who said, "I thought you knew everything."

"Oh, _I_ do. It seems as if you and your crew are operating under some misinformation." He spun on his heel and looked at the duo. "Isn't that right, Johnny boy?"

Q didn't miss the look of surprise that passed over the hologram's face. "How do you..."

The Spartan spoke. "I have never lied to the captain or anyone on this vessel, sir."

He actually thought he was part of Starfleet, Q realized with a wide grin. This could be a lot of fun.

Before he could capitalize on this newfound -and well-deserved- respect, he was rudely interrupted. "Q is not a member of Starfleet, Master Chief." There was Jean-Luc messing with his plans again, Q thought with a wave of aggravation. "He is a-"

"God among men?" Q suggested.

"Annoyance was closer to what I was thinking."

"My point still stands." He walked around the Spartan. "What is your mission, Jean-Luc? To run a diagnostic on this ring? To study it?"

He snapped his fingers and suddenly appeared next to Picard. He lowered his head to speak in his ear. "More importantly, what is _their_ mission?"

An uncomfortable silence settled over the bridge. Q clucked his tongue. "Jean-Luc, you are far too trusting. No one travels back in time from an alternate universe just do to do some land surveying."

A flash of uncertainty passes over Jean-Luc's face and Q knows that he has him right where he wants him. "Go on, ask him. He won't lie, you know. Neither will she."

"Master Chief, as much as I hate to admit it, Q does have a point. If you have another objective, I need to know what your objectives are," Picard said.

"It's classified."

"I could tell you, if you want, Jean-Luc." He grinned. "It _is_ rather juicy."

He pushed too soon. Jean-Luc turned his frustration on him. "Not now, Q."

"If you change your mind, just whisper my name and I'll be here." Then, in a flash, he disappeared. He had cast enough doubt on Chief's character to satisfy the Continuum.

His meddling could mean the destruction of this universe, however. Which really was a pity if Q did say so himself.


	10. Chapter 10

**Onward with the crossover magic! As always, I'd love to know what you think! :D :D  
**

* * *

Cortana was on Reach.

Here, in this perfect recreation of her home, she could forget that she and John were in some unknown universe, trying to protect humanity from the atrocity of the Halo ring.

Here, she could almost imagine having a conversation with Doctor Halsey about ONI and their ridiculously stringent protocols.

Here, she could forget that she is dying.

Here, isn't real, of course. But the _Enterprise_'s holodeck makes it very convincing and almost allows her to forget everything that happened on the bridge.

Almost.

When the captain had ordered her and John off the bridge while he and the rest of the senior staff had a meeting, she had transferred herself to the holodeck where most of her program had remained, working on getting her back to functioning properly. She hadn't even told John she was leaving.

The yellow grid that awaited her was too oppressive for her, so she quickly created a familiar environment for her to work in. In original Sword Base, she had worked with the doctor to achieve greatness. She hoped she was able to achieve that once more.

As she walked through the halls of the holographic base, she stepped through the doors to Halsey's lab. The interface in the center of the room was still tied to the _Enterprise_'s main computer. She accessed the information and frowned. The progress was going slower than she would have liked.

She was tempted to blame the slower computer, but she knew that most of the problem lay with the amount of corruption in her files. It was amazing that she had even been able to be reactivated.

Commander Data was the one to thank for that. She and he had implemented the positronic protocol to her matrix. It took a bit of work to get the two differing technologies to be compatible, but they had finally got them to communicate with each other.

Maybe she would be able to complete this mission with John, after all.

She hadn't expected that she would ever see him again. After their last mission, after she had almost failed to protect him, she had resigned her fate that her second chance to work with the Spartan was over.

But somehow, she made in here.

The doors to the holodeck opened. John walked in, helmet on his head.

Creating a holographic interface to buffer her systems, instead of relying on John's helmet, had been her first priority after she had been activated on the holodeck. It was too difficult -too distracting- to see John's face as Data rambled on about their idea to salvage her program.

It wasn't the worry or concern that bothered Cortana.

It was the unabashed hope on his face.

Within minutes, she had created the interface and John had his customary helmet in place.

He crosses the room to stand next to her. "You left in a hurry."

"Well, I am busy trying to save my life here."

"Data said he's optimistic." There was a slightly hitch to his voice.

"Everyone on this ship is optimistic, but that doesn't mean that his plan is going to work either," she said, averting her eyes. She didn't want him to see the hope reflected in them.

"It will work." Classic Spartan determination.

"What if it doesn't?" She looked at him, grateful for the reflective visor. "We both know that I shouldn't even be here, John."

"But you are."

"Because you saved me. Or part of me anyway." She crossed her arms. "We both know that what you found after the Composer's destruction is only a fragment of what I used to be."

He took a step closer to her. "You are still Cortana."

"But for how long?" The question caught in her throat. She drew in a breath, forgetting for the moment that it was completely unnecessary and looked at him squarely. "If I die, you have to continue the mission without me. Promise me."

The air in the room got heavy as the weight of her demand pressed upon them.

"I can't."

"What happened to you, John? The man I knew would give up anything for a mission's success, no matter the cost."

He doesn't answer right away. When he does, his voice is quiet. "I learned that sometimes the price is too high to pay."

"John..."

He reached over and put his hand on top of hers. She let out a soft gasp. He _never_ sought out any sort of physical contact from her. "Don't ask me to make a promise that I won't keep. I cannot do without you, Cortana. I've tried."

She knew he had. She twisted her hand around so she could give his a gentle squeeze. "I don't want to say goodbye again," she whispered.

"Then, don't." He nodded towards the console she had been working on. "We'll get you back to normal and then we'll complete our objectives. Together."

"You make it sound so simple. Saving the universe."

"We've done it before."

She raised an eyebrow. "If wasn't for your lack of a cape, I might think you're some kind of superhero or something."

"No. Just lucky."

Her eyebrows furrowed. There was a whisper of a memory that was just out of her grasp. "I said that to you once, didn't I?"

She felt his hand stiffen under hers. "Yes. On the Cairo platform."

Cortana didn't want to admit that she didn't know what he was talking about; that still so many of her memories were locked away in the chip, more than likely too corrupted to ever be of any use. She offered a smile that she hoped didn't look as forced as it felt and pulled her hand away.

"I should get back to work. We have no idea what if the captain is even going to let us stay aboard if his little meeting with his staff."

"He will." John sounded confident.

"But what happens if he doesn't let us get down to the surface?" she countered.

"We'll figure out a way. We always do."


	11. Chapter 11

**Onward with the fic! :D :D  
**

* * *

"I still find no reason to not trust him." Deanna sat across from Jean-Luc, her hands folded in her lap.

"Q's questions did bring to light the Master Chief's unwillingness to be completely open with us," the captain countered.

Deanna seemed unperturbed by his question. "How many times have we had to be less than completely honest in certain situations? I told my shares of lies when I posed as Rakal. You did the same when you claimed you were with Galan."

Jean-Luc shook his head. "Those were different circumstances."

"To us, yes." She drew in a deep breath. "All I sense for them is the desire to complete their mission. The fear I feel from them is real. Whatever Halo is, they know of its danger."

"I just wish they would tell us what that danger is."

"I believe if they felt like they could, they would, sir."

He sighed, trying to figure out what he should do.

It wasn't often that he was torn between two equally compelling arguments. When he had asked the Chief to leave the bridge, he had called a senior staff meeting. Both sides were represented at the table: Data, Geordi and Deanna all fell on the Chief's side while Will and Worf tended to show a bit more caution towards believing the Chief. Only Beverly, who had barely interacted with the Chief, had remained a neutral party.

In the end though, he dismissed his crew, without a decision made.

He assumed it was the indecision that had propelled Deanna to follow him into his Ready Room to make her case for the Master Chief and Cortana.

He walked to his window, cup of tea in hand, and looked at the giant ring that lay in front of the _Enterprise_.

What interest could Q possibly want with it?

That was what unsettled Jean-Luc the most. Why did Q care what happened to the ring?

He frowned slightly before he turned away from the glass. "Perhaps if I-" The door chime chirped. "Come," he called.

When the doors slid apart, Guinan was standing on the other side of them. His eyebrows rose and he straightened. "Guinan? Do what do I owe this visit?"

Deanna stood up and gave Guinan a soft smile. "I'll let you two talk." She walked out of the room as Guinan occupied the chair she had been sitting in.

Jean-Luc settled in his own seat. He barely had time to set down his cup before Guinan spoke. "I heard we had an unexpected visitor."

He wasn't surprised she knew; these sorts of things spread quickly throughout a ship so small as the _Enterprise_. "Yes. Q brought up some concerns about the Master Chief's mission."

"Really?" Her lips pressed together. "What kinds of concerns did he bring up?"

"Details about his mission. Details that the Master Chief refused to reveal."

She looked unfazed by his answer. "And this is surprising? I know you and and your crew have been on numerous classified missions yourself."

"But, I am the captain."

"And he is a Master Chief of the UNSC." She leaned back in her chair and appraised him. "Has he done anything that makes you question his intentions?"

"Guinan, he's been here for over two weeks and hardly anyone knows anything about him."

"Tell me. How many people on your senior staff call you by your first name after serving with you for over seven years?"

He shook his head and set down his cup of tea. "That's not a fair comparison. I am their senior officer."

"And you are a bunch of strangers to John." Her voiced softened. "I've talked with him. You should trust him."

There was something in her tone of voice that caught Jean-Luc's attention. She was hiding something from him. "Why? What is it about him that makes you believe him?"

"You've heard the stories about the origins of my people. How many millenia ago, humans mated with an advanced species which produced the El-Aurian?" She nodded out the window. "That advanced species, the Forerunners, built that."

"You know what that is?"

"I know whispers of the truth. A legend of a terrible weapon that led to the annihilation of the Forerunners and most other sentient life in the galaxy. If my people hadn't fled to a world that was safe from the Halo ring, they would have died too." She paused. "Whatever his mission is, you need to allow him to do it."

"Did he tell you why?"

"Yes." She didn't elaborate.

"Well?"

She shook her head. "I'm not going to tell you. There are some things that you are better off not knowing. You're going to have to just trust my judgment."

A flash of light appeared in the room. When it faded, Q was sprawled across his couch. "Sometimes even she has wisdom, you know."

"Q!"

Guinan barely masked the look of frustration on her face. "Oh, _now_ you think he should listen to me."

"I was originally sent here by the Continuum. I have no desire to see events unfold in the way they were prefer," Q replied. "Since, you and I both know that Jean-Luc is going to listen to your council, I figure my commitment to the Continuum is complete. I failed. Woe is me."

He hopped up and leaned against the desk, crossing his arms. "This plan that was set into motion by _her_ was not sanctioned by the Continuum. Of course, being the prudish bunch they are, most of them got offended and vowed to stop her plan from coming into fruition." He let out a long-suffering sigh. "It hasn't worked before, so I don't know why they were expecting anything different this time around."

Jean-Luc's eyebrows rose. "The Master Chief can be trusted then?"

"As annoying as they are, I can't go against the will of the Continuum. You will have to make your own judgment on the Tin Man. I will just say that..." The rest of his words were mumbled.

Jean-Luc's brow furrowed. "Say what?"

Guinan looked smug. "He _said_ that I was right."

"Don't flatter yourself. Even a broken clock is correct twice a day." He stood up. "I trust that the fate of the universe is safe inside your unprepared hands."

Then, with a snap, he disappeared.


	12. Chapter 12

**Onward with the fic! :D :D  
**

**A word of warning, there is a flashback of a character death. You have been warned.**

* * *

John watched quietly as Cortana moved from one control panel to another. Her hands were steady, her emotions less so.

John couldn't say he was much better.

Though this was the best he had seen her in a long while, he knew she was still losing the battle.

And the Chief hated losing.

John forced him not to think of Cortana's failing health and focused on his main objective of reaching the Halo ring.

If Captain Picard would not allow them to transport to the surface, John was certain that between his might and Cortana's familiarity with the _Enterprise_'s computer systems, they could commandeer a shuttle and make it to the Halo ring with relative ease. The officers stationed aboard the ship were not soldiers and he could use that to his advantage.

For now, he was content to allow the captain to deliberate about his next course of action while Cortana continued to work on repairing her program.

"I have cleared most of the redundant data from my memory banks," she said. Something akin to hope was reflected in her eyes. "It's going to take some time for me to sift through all the Forerunner and UNSC data, but I think I can have full access to my own personal files."

John wasted no time to allow himself to hope. He simply nodded. "Do it."

"When I implement this protocol, my program will go offline. I am going to need you to reactivate me after thirty seconds. We'll know if it works then." Her hand hovered above the control panel. Then, she pressed the button.

She was gone again.

Despite her warning, John's gut tightened at her disappearance. After weeks of waiting and hoping, he had just got her back. He didn't want to think what would happen if he couldn't reactivate her.

Pushing his feelings aside, he counted to thirty. Then, he reached over and activated the button. Three seconds passed.

Nothing.

"Cortana? Are you there?"

"Give me a second." She sounded distracted.

Finally, nearly a minute later, she appeared in front of him. A soft smile was on her face.

"Did it work?"

She nodded. "I remember almost everything of my own history. I remember that day that I saw your picture on Doctor Halsey's wall, thinking how handsome you were-" John felt a blush crawling over his cheeks. "-and I remember that I chose you to be the Spartan I would work with."

She moved to stand directly in front of him. "I remember the _Autumn_, and Halo, and Cairo." Her gaze shifted downwards. "I even remember _High Charity_ with _him_. And I remember you keeping your promise."

"And Requiem?"

She gave a small nod. "The data was fairly corrupted, but I managed to splice enough of it together to get a good idea of what happened there." She looked up into his face. "But after the Composer..."She let out a soft sigh. "...there's not much to work with. I had to use the data from your armor's databanks to fill in the gaps."

"But you remember more than you did."

"Yes, but John..." She placed a hand on his chest, like she had. Before. "The Rampancy is still corrupting my systems."

This was the best he had seen Cortana in years. He was not going to let this opportunity slip away from him. Not like it had on Requiem. Before he had a chance to respond, the doors to the holodeck opened. Captain Picard stood on the other side of them.

He had stepped back quickly when he saw the commanding officer. Cortana's hand dropped awkwardly to her side.

If the captain saw anything, he didn't make a comment on it. He studied the two of them of a second before he spoke. "I have decided to authorize the two of you to beam down to the planet's surface. An away team led by Commander Riker will accompany you. But, first, I'd like some answers."

John exchanged a glance with Cortana. "We cannot tell you anything about the future."

"I understand that, but I would like to know about where and when you came from. I want to understand why you are here and why this mission is so important to you."

Cortana let out a shaky sigh, giving John a sideways glance. "I guess we owe him that much." She closed her eyes briefly.

"When the Chief and I were first assigned to work with each other, humanity was being attacked by a group of religious zealots called the Covenant. Humanity was fighting a failing war. One ray of hope we had was a group of soldiers called Spartans." She nodded her head towards John. "Despite their best efforts, our home world was attacked and destroyed. We were forced to flee. Our ship left the system and we found ourselves at a Halo ring. And there we found something far more dangerous than anything we had ever encountered before."

A infected form of the Flood appeared in the center of the room, frozen in time. Although John knew that it was a holographic projection, his pulse still spiked.

Cortana's voice remained calm as she explained what the Flood were, why the Halo array was created and how Earth had been nearly consumed by the Flood. But, as she started to recount what happened after the two of them were stranded in space for years, her voice started to sound more panicked.

John offered to take over the rest of the narrative, but Cortana insisted on telling their history.

"The Composer was a weapon of mass destruction. It would have killed everyone on Earth, but the Chief stopped it." She offered him a shaky smile.

Picard, who had been silent the entire time, frowned. "But that doesn't explain how you got _here_."

John finally spoke. "We're here because I failed in my objectives."

The plan was simple. After the destruction of Requiem, ONI studied the piece of the map that Thorne had held onto that contained information about Forerunner installations that they had yet to encounter. After reviewing the map for nearly a year, ONI had made a discovery. The data -the minds of those who had been taken that day in New Phoenix- had been siphoned to a facility known as the Cache. And there was evidence that Cortana's program had survived the destruction of the Composer.

John had immediately volunteered to go to the installation. Thorne, and the rest of Fireteam Majestic, had asked to be part of the mission as well. At the beginning, everything was going according to plan. But then, they had found her.

Halsey.

She had been dying from a gunshot wound to the abdomen. Then, she had explained how this had been a trap and how the Didact, obsessed with the destruction of humanity, had made a deal with the Gravemind who had been slowly rebuilding after he had nearly died when the Ark had been destroyed.

She had slipped him a chip which held a fragmented Cortana. "It is the best I can do, John. Take care of her." Then, Halsey had died.

She had been the first of many casualties that day.

The UNSC, Separatists, Covenant and Insurrectionists worked together to fight against the impossibly powerful enemy. In the end, only a scant few million hadn't been infected.

"Our universe had been overtaken by the Flood." Cortana's voice cut through the memories. "The _Infinity_ was the last UNSC ship and we knew we could only run for so long. Then, after 18 months, the Gravemind found us."

Lasky, Palmer, and the others -even Roland- had been consumed by the Flood within hours. Trapped in a storage bay with a shotgun and less than a dozen shells, John had finally allowed himself to concede defeat.

But then, before the Flood could attack, a portal had opened inside the bay. Without hesitation, John had jumped in with Cortana's chip in his armor.

"We managed to escape, thanks to the Librarian." Cortana's voice was strong. "She was from the Foundation. The original timeline where all possibilities begin. There, she offered us a deal to do what we couldn't do in our own time."

"Save humanity." John's words hung in the room.

Picard's eyebrows rose. "Then, this isn't the first time you've traveled to other universes."

"No. We've dealt with everything from Cylons to Ancients." Cortana's chin jutted forward. "Someday, we're going to save our people."

"How?"

"By finding a cure for the Flood infection."


End file.
